Water Adjustment – Chlorine Removal

Lately, there has been some talk in the club forum about water used in brewing. We (Chris K and Ryan D) thought it would be a good idea to lay out some water basics for someone who has never thought about water. Water is the main ingredient in beer, but it shouldn’t be the first thing a brewer thinks about when they make beer. There are a few small things to worry about to avoid off-flavours. But other than that, playing with water is much like seasoning your food. Adding salt to a dish can make it pop, but you are never going to take a bad meal and make it good with salt. In a similar way, playing with water is not going to make the beer good on it’s own.

The first important thing about water in brewing is that if you have bad tasting water, you probably don’t want to use it. However, the old adage of good tasting water makes good tasting beer is not always true either. With a few simple cheap processes, you can turn that good beer into a great beer.

Base water

For your base water, you want to make sure you are using water with some calcium in it. This is pretty easy to do in the “True Grist” area. Calcium is important for getting a proper mash pH, enzyme activity in the mash, and yeast health. Don’t use pure RO, and try to stay away from softened water. Softened water is also usually full of sodium (or potassium), which can come across as sour and metallic. Also, try to stay away from using a garden hose to deliver your water as that can leave some plastic-like flavours in your final beer.

Removing Chlorine


Chlorine and chloramine are the standard methods used to disinfect water. However, they can react with malt to produce chlorinated compounds that produce “chlorophenolic” off-flavours, often described as plastic, bandaid or medicinal. By removing these before we add our grist, we can avoid these off flavours.

In Waterloo Region, most water does or may contain chloramines. In Guelph, only chlorine is used. Some brewers will use bottled spring water which is generally disinfected with ozone instead of chlorine, or you may have a private well without chlorine and instead treated by UV. Determine which method is used for treating your water so that you can efficiently and effectively treat and remove the chlorine compounds.


Time or Boiling

Chlorine on it’s own doesn’t like to be dissolved in water. If given enough time, usually less than overnight on the homebrew scale, the gas will naturally escape the water and leave it chlorine free. Like all gases, the solubility and stability of chlorine decreases as the temperature increases. This is very much like carbonating a keg of beer with CO2 where the lower temperature means less pressure required. By the time you reach a boil with chlorinated water, all of the chlorine will be gone. Chloramine is much more soluble in water and isn’t a gas, so this isn’t an effective method for removing it!

Sulfite (Campden)

In water treatment, one of the reasons chloramines are used is because they are more stable than chlorine. They can be used at lower rates while still doing the same job as chlorine. However, this stability is a big negative for homebrewers who want to remove it. The aforementioned trick of boiling or waiting for the chloramine to degas just will not work on reasonable time scales. To remove chloramine, one can add sulfites — commonly called campden in the homebrew community — at a rate of 1/4 campden tablet per 5 gallons. The sulfite reacts with the chloramine to produce ammonium and chloride ions in the beer, both of which are actually beneficial to beer. Sulfites also expedite the removal of regular chlorine in a similar way. No need to worry about dosing with absolute precision- excess sulfite will react with dissolved oxygen in the mash and act as an antioxidant.   

Campden tablets (or Sodium Metabisulphite) can be used to remove chloramines from water.

Ascorbic Acid (Vitamin C)

The method is very similar to campden. The ascorbic acid is added at approximately 7.5 mg/L. It produces chloride and dehydroascorbic acid as reaction products. When used with chloramine it also produces ammonium which is beneficial to yeast health. It also takes a few minutes to react with chloramine, so let acid sit for approximately 20 minutes. As an acid, it will also reduce the pH, so that should be considered. Neither of us have used this method, so we are unsure if there are any downfalls to using this compared to campden. However, there is an advantage over campden in that sulfites tend to inhibit yeast activity if there is too much left in the wort. Thanks to Dave for letting us know about the potential of using ascorbic acid for this!

Carbon Filtration

This method is a favourite among some homebrewers. Essentially, it can improve the flavour of water without making any significant impact on the mineral content. These filters are quite effective at removing chlorine- which reacts with the actual charcoal- but are said to be less effective at removing the more stable chloramines. Slower flow rates and larger filters improve this, however it seems that the methods commonly used in homebrewing are effective for both chlorine and chloramine.  

Click here for more information on removing chloramines from water.

Putting it into practice

We each deal with different water based on where we live. We will describe how each of us deals with our water.


I use Guelph water which has chlorine in it. I start by bypassing my water softener (there’s a valve on the back), and collecting all of my water in buckets (or brew pot) with a loose fitting lid at least one day before brewing. If I forget to do that, I heat the tap water to boiling for a few minutes prior to using.



I use Cambridge water, which means I have to deal with chloramines. As my pots fill, I add sodium metabisulfite. I use the powdered form. At one time I worked out the exact amount needed with a precise scale, and concluded with knowing I need only a very tiny bit- whatever sticks to the end of my little finger. If I used any, it was probably enough. Plus, you have a tool attached to your face that can validate that it worked- your nose. Any chlorine smell to the water should vanish. 

In the next post, we will talk about how to control the high-alkalinity water that we have to deal with in this area. This will be all about why it’s important to get your pH in check, and how to do it.